17-07: Myceliophthora thermophila liquefies pretreated lignocellulosic biomass at high solids loading

Efficient, mild depolymerization of plant cell wall structural components is central to the realization of a commercial biorefinery that delivers a diversity of renewable liquid transport fuels and other high-value chemicals. Commercial cellulases, sourced almost exclusively from mesophilic fungal species are not efficient enough to meet the requirements of economically viable bioprocesses. Typically, temperatures above 50°C are required for improved liquefaction of feedstock at loadings in excess of 15%. It is thus imperative to develop novel, efficient, thermophilic cellulases with tolerance to high solids loading. Such biocatalysts could potentially be used for the design of synthetic minimal enzyme mixtures or as additives to existing commercial enzyme mixtures for improved biocatalysis.

This presentation will cover a strategy for the evaluation of biomass liquefaction by enzyme mixtures secreted by thermophilic fungi grown on a broad spectrum of pretreated wood biomass types and the identification of novel, promising enzyme candidates in fungal secretomes.  Promising enzyme components were identified by mass spectrometry and released sugars analyzed by high performance anion exchange chromatography coupled with pulse amperometric detection. Particularly, Myceliophthora thermophila was found to secrete an enzyme mixture that  liquefies hardwoods and softwoods pretreated by thermo-mechanical, organosolv, kraft and steam explosion methods, releasing mainly glucose, xylose and galacturonic acid. Our strategy is a promising tool for the discovery of efficient biocatalysts for application in biorefineries.